You must have had an X-ray in a hospital or a clinic. Phase contrast technology is now attracting attention as an innovative technique in X-ray. Before explaining phase contrast technology, the outline of X-rays will be described. The X-ray absorption difference (absorption contrast) of the body structure (such as bones and muscles) are recorded to films as image information by setting a cassette that works as X-ray film for a patient and radiating X-rays, as shown in Fig. 1. X-rays are then derived through the development process.